• Preheat oven to 350 degrees F if using a glass pan, or 375 degrees F, if using a metal pan.
• Spray a 13x9-inch baking pan with baking spray and set aside.

Crust:

• In a medium bowl whisk together sugar, flour, baking powder, and salt.
• Add the diced butter and using a pastry cutter, or a fork, work the butter into the flour until the mixture resembles coarse sand. If the mixture is too "wet", add a bit more flour.
• Add the lightly beaten egg and mix well, until the dough starts to hold together, it still should be crumbly. I prefer to mix it in a stand mixer.
• Gently press a little more than half the dough into the bottom of the prepared pan. Set aside the remaining dough, it will be used for the crumb topping.

Peach layer:

• In a large mixing bowl whisk together the white and bron sugar, cornstarch, nutmeg, and cinnamon.
• Add the diced fruit and toss to combine.
• Add the lemon juice and toss to coat. Pour the mixture on top of the crust and spread it evenly.
• Sprinkle the slivered almonds on top.
• Using your fingers, press together small handfuls of the remaining dough to create a few clumps. Scatter them and remaining crumbled topping on top of the fruit layer.

Bake:

• If using a glass pan, bake at 350 degrees F for 50-55 minutes or until lightly browned and bubbly.
• If using a metal pan, bake at 375 degrees F for 40-45 minutes or until lightly browned and bubbly.
• Removee from the oven and cool completely on a wire rack, then chill before icing and slicing.

Almond icing:

• In a medium bowl, whisk together all the ingredients, until smooth and without lumps. Drizzle on top of the chilled bars.
• Slice and serve.